JP2003191935A - Metallic container having coated inner surface and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce microcracks and micropeeling to the utmost by enhancing working resistance in postworking for a metallic container in which a corrosion- resisting coating is applied to an inner surface. <P>SOLUTION: In this metallic container 10 in which plastic working, having a high degree of working, is applied to the vicinity of an opening after the application of the coating to the inner surface, a coated film, which is formed by the coating, is composed of: a highly working-resisting first layer 12 which is provided in a part having a high degree of working; and a highly corrosion- resisting second layer 13 which is provided on the whole inner surface of the metallic container 10, including the first layer 12. The first layer 12 is formed of an epoxy phenol-based resin coating containing a low phenol content and no pigments; and the second layer 13 is formed of an epoxy phenol-based resin coating containing a high phenol content and the pigment. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal container having an inner surface coated. More specifically, after painting the inner surface, a metal can that has been subjected to mouth-drawing or screwing near the opening, or after painting the inner surface, fill the contents,
It is related to the improvement of the coating of the extruded tube made of metal for the hem and the bending process.

[0002]

2. Description of the Related Art Conventionally, in order to protect the inner surface of a metal container from the contents, a synthetic resin coating film having high corrosion resistance is provided on the inner surface of the metal container. As an example of a metal container having such an inner coating film, a metal can 100 having an inner coating film shown in FIG. 12 is known. This metal can 100
It consists of a can body 101 and a coating film 102 provided on the inner surface thereof. The can body 101 is formed by plastically deforming a metal plate such as aluminum by pressing, and has a cylindrical body portion (side wall) 103, a bottom portion 104 that closes the lower end thereof, and a truncated cone shape that is continuous from the upper end of the body portion. Shoulder portion 105 and a cylindrical neck portion 106 extending upward from the shoulder portion 105. A curling (bead) 107 is provided on the upper end of the neck portion 106 so that the curling (bead) 107 is wound around the neck portion.
6a is formed.

To manufacture such a metal can 100,
In the case of a drawn and ironed can, first, a blank material obtained by punching out a thin metal plate in a circular shape is deep-drawn by a press to form a cylinder with a bottom, and further the body is ironed to reduce the wall thickness. The inner surface of the obtained bottomed cylindrical can body is powder-coated or spray-coated to form the coating film 102. After forming the coating film on the inner surface, the shoulder portion 105 and the neck portion 106 are formed by mouth-drawing. Further, the curling 107 is formed by curling. In the case of a squeezed ironing can having a threaded portion, a stepped portion and a screw are further formed by spinning or the like.

Further, in the case of an impact can having a threaded portion used for an aerosol container, a thick metal plate is punched out in a circular shape, and the shape is adjusted to form a slag, and a bottomed cylindrical shape is formed by impact processing. Then, the inner surface is painted, the shoulder portion and the neck portion are formed by mouth-drawing, and the bead portion is formed by curling.

As described above, the coating film on the inner surface of the metal container is generally formed after the metal plate or slag is plastically worked into a cylindrical shape having a bottom, and after the painting, the shoulder portion is formed by necking. And forming the neck (post-processing). In this way, the inner surface coating film is formed before post-processing. When the inner surface coating is applied after processing, uneven coating or unpainted parts appear on the screw part and neck part (necking part), and This is because it is impossible to sufficiently achieve the function, that is, the corrosion prevention of the metal container by the contents.

Various coating films 102 for the inner surface coating are used depending on the nature and purpose of the contents. For example, when it is desired to obtain a coating film excellent in metal corrosion prevention and can body workability / adhesion, epoxy / phenolic resin coating is applied. In that case, it has been proposed to apply an oil-based resin coating film containing zinc oxide particles on the bottom of the can to a pre-coat material in which the can body is separately coated with an epoxy / phenolic coating film (JP-A-61). -47344). This can prevent sulfur blackening on the inner surface of the metal container due to marine products. Further, JP-A-5-138125 discloses a method of separately coating the can bottom and the can body by a powder coating method and baking them at one time. This product can be baked once by applying the same paint separately.

On the other hand, Japanese Patent No. 25626243 discloses that
On the inner surface of the steel aerosol product filled with the water-based aerosol product, the underlayer is composed of the coating layer of the epoxy / phenolic resin coating with the thickness of 1 to 8 μm, and the top coating layer has the glass transition temperature of 3 to 20 μm. An inner surface coating technique having a two-layer structure composed of a coating layer of a vinyl / organosol resin coating material at 50 ° C. or higher is disclosed. It is said that this product can prevent the occurrence of cracks due to neck-in processing and winding tightening processing. In addition, JP-A-3-725
Japanese Unexamined Patent Publication No. 78 discloses an internally coated can whose base layer is a water-based epoxy / phenolic resin coating having a thickness of 1 μm or less and whose surface layer is a water / water-dispersible epoxy acrylic phenolic resin coating having a thickness of 2 to 20 μm.

Further, a precoat material having a two-layer coating film on the entire surface is subjected to drawing processing (DRD processing, DI processing, etc.),
A technique for forming a metal can having an inner coating film is known. For example, a sulfur-containing food container coated with an epoxyphenol resin paint containing an AI pigment as a primer layer (underlayer) and coated with a polyolefin or unsaturated polyester containing zinc oxide powder for preventing coloring due to the content on the surface thereof. (Unexamined Japanese Patent Publication No. 56-32237), or a vinylorganosol-based resin coating for the underlayer and an epoxyphenol-based resin coating for the surface layer, which suppresses absorption of dyes contained in foods such as crabs baked twice. A metal can (Japanese Patent Laid-Open No. 2-242743) and the like are known.

Further, there is known a technique for preventing the uncured coating film from sagging and generating pinholes / cracks by performing preliminary drying or intermediate drying treatment between the first coating and the second coating when the coating is performed twice. (Japanese Patent Publication No. 63-44026, Japanese Patent Publication No. 1-34584, JP 2000-10
No. 4013). On the other hand, a technique of coating film using UV ink is known and used in cosmetics and the like (Japanese Patent Laid-Open No. 60175/48, Sho 61-29009).
No. 9 public information). However, since the UV ink contains a photopolymerization initiator and a photosensitizer, its safety to the human body is unclear and storage stability is also problematic. Not suitable for along with. JP-A-8
According to the publication No. -173898, an ultraviolet curable resin is printed on the outer surface of a metal food container, a polymerizable monomer containing no photopolymerization initiator and a photosensitizer is applied thereon, and then ultraviolet light is applied. It is disclosed that the outer surface of the container does not contain a photopolymerization initiator and a photosensitizer by irradiation and curing. However, UV ink is not used for coating the inner surface of the container.

On the other hand, in a metal-based extruded tube,
A technique is known in which an undercoating film such as epoxy is formed on the inner surface of the tube, and a coating layer by powder coating is formed on top of it to make the part that becomes the fastening part thin (the undercoating film may be exposed). (Japanese Utility Model Publication No. 59-16850). This is intended to save powder paint and improve appearance. Furthermore, for the purpose of improving the tightness of the folded part,
There is also known a tube container in which the portion to be the tightening portion on the inner surface of the powder-coated tube is unpainted (JP-A-55).
-116558 publication).

[0011]

The conventional metal container, which is formed into a tubular shape, is subjected to an internal coating having corrosion resistance, and then subjected to severe plastic working such as necking, curling, or screwing, Cracks or peeling may occur on the inner coating film such as the screw portion or the necking portion. Even if the coating film is not cracked or peeled off visually, minute cracks or pinholes may occur, and the energization value may be poor in the energization test (the current value when energized is high).

An object of the present invention is to improve the working resistance in the post-processing of a metal container coated with an inner surface having corrosion resistance, and to improve the energization value by minimizing minute cracks and peeling. There is. Further, it is a technical object of the present invention to provide a method for producing a metal container which has good work resistance during post-processing and has high corrosion resistance to the contents.

[0013]

The metal container having an inner surface coated according to the present invention is a metal container which has been subjected to a plastic processing with a high degree of processing in the vicinity of the opening on one end side after the inner surface is coated. And a coating film formed by the coating has a first layer having a high work resistance provided at least in a portion having a high workability and a second layer having a high corrosion resistance provided in at least a portion having a low workability, The inner surface of the container, which is entirely covered with the first layer and the second layer, is coated. Here, "the part with a high degree of processing" and "the part with a low degree of processing"
The above refers to the plastic working performed after the inner coating is applied, and does not relate to the degree of working before the inner working. In other words, even if the part that has been processed with a high degree of processing before the inner surface coating is not processed after the inner surface coating, or if only the processing with a low degree of processing is performed, here, the part with a low degree of processing is processed. Is. Further, "a portion having a low degree of processing" includes a portion which is not processed. Such a metal container is preferably a monoblock container formed by impact processing, drawing or drawing and ironing. Further, it is preferable that the mouth portion of the metal container is screwed. Further, it is preferable that a third layer made of UV ink or a hot melt agent is provided on the entire inner surface of such a container.

In such a metal container, it is preferable that the first layer is provided on the entire inner surface of the container and the second layer is provided on a portion or the whole of the first layer having a low workability. Further, the first layer is provided in a portion having a high degree of processing,
The second layer may be provided on the entire inner surface including the top of the first layer. In that case, the first on the second layer
The coating film of the third layer made of the same material as that of the first layer may be further provided in the range corresponding to the layer. Further, the first layer is provided in a portion having a high workability, the second layer is provided in a portion having a low workability, and the first layer is stacked on the first layer in the vicinity of the boundary with the first layer. Good.

As the inner coating film, it is preferable that the first layer is made of an epoxy / phenolic resin coating material having high workability and the second layer is made of an epoxy / phenolic resin coating material having high corrosion resistance. In the case of the metal container having the third layer, the first layer and the third layer are made of epoxy / phenolic resin coating material having high workability, and the second layer is made of epoxy / phenolic resin coating material having high corrosion resistance. Is preferred. Further, the second layer is an epoxy / phenolic resin coating material containing a pigment, and the first layer is an epoxy / phenolic resin coating material containing no pigment or having a pigment content smaller than that of the second layer. it can. Further, the first layer contains 10 to 30 wt% of phenol, especially 15 to 20 wt.
% Epoxy / phenolic resin paint, the second layer contains 20-50 wt% phenol, especially 22-30 wt%
% Epoxy / phenolic resin paint and first
It is preferred to use an epoxy / phenolic resin coating which has 1 to 20 points, and particularly 2 to 10 points, less phenolic component than the second layer. The "point" here is
It means the difference of the numerical value of percentage.

The first layer is an epoxy-phenolic resin paint using an epoxy resin having a low molecular weight, for example, an average molecular weight of 2,000 to 7,000, and the second layer is a high molecular weight, for example, an average molecular weight of 5, 000-20,000
A metal container which is an epoxy / phenolic resin paint using the above epoxy resin is preferable. The first layer is a water-based epoxy / acrylic resin coating using a low molecular weight epoxy resin, and the second layer is a water-based epoxy / acrylic resin coating using a high molecular weight epoxy resin. Containers are preferred.

In the method of manufacturing a metal container having an inner surface coated according to the present invention, a cylindrical container body is formed from a metal material, and at least the inner surface near the opening provided at one end of the container body has a work resistance. A high first layer coating is applied, and then a second layer with high corrosion resistance is applied wet-on-wet so that at least a part of the first layer is overlaid, the coating film is cured, and then the opening is formed. It is characterized in that the vicinity of the portion is subjected to plastic working with a high working degree, and the entire inner surface of the container is covered with the first layer and the second layer. A second aspect of the production method of the present invention is to form a cylindrical container body from a metal material, apply UV ink to the entire inner surface of the container, and then cure the coating film by UV irradiation. Next, at least the inner surface near the opening provided at one end of the container body is coated with a first layer having high work resistance, and then wet-on so that at least a part of the first layer overlaps the first layer. Wet the second layer with high corrosion resistance, harden the coating, and then subject the entire inner surface of the container to the plastic processing with a high degree of work in the vicinity of the opening. It is characterized by being covered. A second aspect of the metal container of the present invention is a metal container, which has been subjected to plastic working with a high working degree in the vicinity of the opening on one end side after applying the coating on the inner surface, and the coating film by the coating is applied. Having a first layer made of UV ink provided on the entire inner surface of the container and a second layer made of a solvent paint having high corrosion resistance or high workability laminated on a part or all of the first layer. Characterize. Further, a third aspect of the metal container of the present invention is a metal container, which has been subjected to plastic working with a high degree of working in the vicinity of the opening at one end after coating on the inner surface, wherein the coating film by the coating is Having a first layer made of a hot-melting agent, which is provided on the entire inner surface of the container, and a second layer made of a solvent paint having high corrosion resistance or workability, which is laminated on a part or all of the first layer. Is characterized by. The thickness of the coating film of the first layer is preferably 3 to 100 μm. Further, it is preferable that the first layer is made of a radical polymerization type UV ink and the second layer is made of an epoxy resin paint.

[0018]

In the metal container having the inner surface coated according to the present invention, since the inner surface of the first layer having high work resistance is coated at least in the vicinity of the opening on one end side, the metal container in the vicinity of the opening is coated. Even when processing with a high degree of processing is performed, the inner coating film is unlikely to crack or peel off at that portion. Therefore, the contents are less likely to penetrate the coating film and corrode the metal surface.

On the other hand, since the second layer having a high corrosion resistance is provided at least in the portion having a low workability, the corrosion resistance is particularly high in those ranges, and therefore the corrosion or discoloration of the metal surface due to the content is small and the content is It is unlikely that the metal will melt inside. Therefore, as a metal container, the corrosion resistance is high as a whole in the range of high workability and the range other than that. Further, in the case of the monoblock container in which the metal container is formed by impact processing, drawing processing or drawing and ironing processing, since there is no seam, cracking or peeling of the inner coating film is unlikely to occur. Furthermore, even when the mouth of the container is threaded, the inner coating film is unlikely to crack or peel off.

In a metal container in which the first layer is provided on the entire inner surface of the container and the second layer is provided thereon, the metal surface is seamless.
As it is covered with one layer, it has high durability. Also, the first
The layers can be easily applied with conventional coating equipment. Further, since the second layer is provided on the first layer, the durability is even higher. Moreover, since it directly contacts the contents, it has a high protective effect on the contents. When the second layer is provided on the entire surface of the first layer, the conventional coating device can be used as it is. Furthermore, since the first layer is entirely covered by the second layer, the protective action against the contents is further enhanced.
The second layer is less likely to be cracked during processing due to the cushioning effect of the first layer even in a portion having a high degree of processing. Further, when the second layer is provided only on a portion having a low workability, the paint can be saved.

In the metal container in which the first layer is provided only on a portion having a high degree of processing and the second layer is provided over the entire area including the first layer, the coating material for the first layer can be saved. Furthermore, the first layer, which is not so high in corrosion resistance, is protected by the second layer, which is high in corrosion resistance. Further, since the relatively hard second layer is provided on the relatively soft first layer, there is an advantage that cracking and peeling are less likely to occur as compared with the case where it is provided directly on the metal surface.
In this way, the first layer and the second layer have mutually complementary actions.

In this case, further, in the metal container in which the third layer made of the same material as the first layer is provided in the range corresponding to the first layer from above the second layer, the workability of the portion having a high degree of workability is high. Further improve.

In a metal container in which the first layer is provided in a portion having a high degree of processing, the second layer is provided in other portions, and the first container is overlaid on the first layer in the vicinity of the boundary with the first layer. ,
Since it is covered with almost one layer as a whole, the first layer and the second layer
It is possible to save the paint of each layer, and the high workability is high in the workability, and the low workability is high in the corrosion resistance. Therefore, cracks and peeling are unlikely to occur even in a portion with a high degree of processing, and the corrosion resistance to the contents as a whole is high.

When the first layer of the inner coating film is made of an epoxy / phenolic resin coating material having high workability and the second layer is made of an epoxy / phenolic resin coating material having high corrosion resistance, the first layer and the second layer are formed. Since it is a paint of the same quality, the sealability and adhesion at the boundary between both layers are high. Therefore, peeling does not occur at the boundary even if the film is drawn after forming the coating film. Further, the epoxy / phenolic resin coating material is a curable coating material, and has a relatively high adhesiveness to a metal and excellent workability and corrosion resistance as compared with other synthetic resin coating materials. Therefore, the first layer with high workability is
This means that the workability is more excellent than that of the second layer, and that the second layer is more excellent in corrosion resistance than the first layer. By separately coating with the second layer, there is less cracking and peeling in areas with a high degree of processing than in the case of a single layer coating of epoxy / phenolic resin paint, and corrosion resistance in areas with a low degree of processing is further improved. It means getting higher. In addition, the third
Even when the third layer of the metal container having layers is made of an epoxy / phenolic resin coating having high work resistance, peeling between layers is unlikely to occur. The two layers are a coating film of an epoxy / phenolic resin containing a pigment, and the first layer is a coating film of an epoxy / phenolic resin containing no pigment or having a pigment content lower than that of the second layer. If the second layer is the first
Harder than the layer and has high corrosion resistance. The first layer is relatively flexible and has high workability. Furthermore, when the first layer contains no pigment, it is inexpensive.

When the first layer is a pigment-free epoxy / phenolic resin coating and the second layer is a pigment-containing epoxy / phenolic resin coating, the pigment-free first layer is relatively flexible, High work resistance. Further, since it does not have a pigment, it is inexpensive. The second layer containing the pigment is
Relatively hard and highly corrosion resistant.

The first layer contains 10 to 30 w of phenol.
t%, especially 15 to 20 wt% epoxy-phenolic resin paint, and the second layer contains 20 to 50 w phenol
t%, especially 22 to 30 wt% of epoxy / phenolic resin paint, and when the phenol content of the first layer is 1 to 20 points, especially 2 to 10 points less than the phenol content of the second layer, The same effect is obtained. In addition, epoxy for the first layer (or second layer)
The phenolic resin coating material may be stored, divided at a predetermined ratio at the time of use, and then a phenol component may be added to one side to polymerize (or the phenol component may be removed).

In the case of a metal container in which the first layer is an epoxy / phenolic resin coating material using a low molecular weight epoxy resin and the second layer is an epoxy / phenolic resin coating material using a high molecular weight epoxy resin, As it is a material of the same quality, it has high adhesion. Epoxy / phenolic resin paints are used as solvent-based paints by mixing an epoxy / phenolic resin with an oily solvent. Cans other than beverage cans, such as hair dyes and gasoline additives, are stored in the cans. Suitable for It is also possible to prepare a coating material using an epoxy resin having an appropriate molecular weight and adjust the molecular weight at the time of use to adjust the coating materials for the first layer and the second layer.

A metal using a water-based epoxy / acrylic resin coating using a low molecular weight epoxy resin for the first layer and a water-based epoxy-acrylic resin coating using a high molecular epoxy resin for the second layer. Since the container uses a water-based paint, it has a good flavor and is suitable for beverage cans (normal squeezed and squeezed can, screw squeezed and squeezed can, etc.).

In the method for producing a metal container with an inner surface coated according to the present invention, a cylindrical container body is formed from a metal material, and at least the inner surface near the opening provided at one end of the container body has high workability. Since the first layer is applied in advance, even if the opening is processed with a high degree of processing, the coating film is unlikely to crack or peel off. To another portion, a second layer having high corrosion resistance is applied on the first layer by wet-on-wet so that at least a portion of the second layer overlaps with the first layer.
Corrosion resistance is particularly high in the range of low workability of metal containers. Therefore, the inner surface of the metal can be sufficiently protected from the content, and the content can be protected from the metal. Furthermore, since the coating films are stacked wet on wet, the coating process can be shortened. Moreover, since the boundary portion of both layers has high adhesion, the contents are less likely to permeate from the boundary portion even if plastic working with a high working degree is performed near the opening. In addition, the second aspect of the manufacturing method of the present invention has all the features of the above-described manufacturing method and thus exerts its action. Further, before coating the first layer and the second layer, the entire inner surface of the metal container. Since the UV ink is coated on and cured by ultraviolet irradiation, a coating film having higher corrosion resistance and workability can be provided with minimum equipment investment and time. Further, since the UV ink is cured by UV irradiation before coating the first layer and the second layer, the photopolymerization initiator and the photosensitizer in the UV ink are not applied to the first layer and the second layer. Less likely to be mixed. In the second aspect of the metal container of the present invention, since the first layer made of UV ink is applied to the entire inner surface of the container, the number of pinholes is small, the content is small, and the content penetrates the inner coating film. There is little risk of corroding the metal surface.
Further, since the coating film can be formed to a desired thickness,
An inner coating film with few pinholes can be formed.
When the second layer made of a solvent-based paint having a high workability is provided at least in a portion having a high workability between the first layer and the metal surface, the inner coating film is further less likely to be cracked or peeled off at that portion. Further, when the second layer made of a solvent-based paint having a high corrosion resistance is provided at least in a portion having a low workability, the corrosion resistance of the inner coating film with respect to the contents is further improved. When the second layer is provided on the entire surface of the first layer, UV ink does not exist on the surface of the coating film and does not come into contact with the contents, so that it is suitable for long-term storage. In the third aspect of the metal container of the present invention, the first layer made of the hot-melting agent is applied to the entire inner surface of the container, and therefore, the same action as the second aspect described above is exhibited. Furthermore, since the hot melt agent does not use a photopolymerization initiator or a photosensitizer, it has little effect on the human body. In such a metal container, by setting the thickness of the first layer made of the UV ink or the hot melt agent to 3 to 100 μm, the above-described operation can be most effectively achieved. When the first layer is a radical polymerization type UV ink and the second layer is made of an epoxy-based oil paint,
The weldability between the laminated layers is high, and there is little risk of peeling.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a metal container having an inner surface coated and a method of manufacturing the same according to the present invention will be described below with reference to the drawings. FIG. 1a is a sectional view showing an embodiment of the metal container of the present invention, and FIG. 1b is an enlarged sectional view of a main part thereof. FIG. 2a is a sectional view showing another embodiment of the metal container of the present invention, and FIG. 2b is an enlarged sectional view of a main part thereof.
FIG. 3 is a side view showing still another embodiment (impact can having a screw portion) of the metal container of the present invention. FIG. 4 is a sectional view showing still another embodiment (normal aerosol can) of the metal container of the present invention. FIG. 5 is a sectional view showing still another embodiment (small aerosol can) of the metal container of the present invention. FIG. 6 is a side view showing still another embodiment (a squeezed ironing can having a screw portion) of the metal container of the present invention. 7 and 8 are cross-sectional views showing still another embodiment of the metal container according to the present invention. FIG. 9 is a sectional view showing still another embodiment (metal tube) of the metal container of the present invention. 10 and 10 are cross-sectional views of a metal container according to still another embodiment of the present invention (metal tube) before and after post-processing.

A metal container (metal can) 10 having an inner coating film shown in FIG. 1 comprises a can body 11 and coating films 12 and 13 provided on the inner surface thereof. The can body 11 is, for example, a monoblock can made by plastically deforming a metal plate such as aluminum by pressing, and is continuous from a cylindrical body portion (side wall) 14, a bottom portion 15 closing the lower end thereof, and an upper end of the body portion. It comprises a truncated cone-shaped shoulder portion 16 and a cylindrical neck portion 17 extending upward from the shoulder portion. A curling 18 (a flat surface may be formed on the curling 18 in some cases) is provided on the upper end of the neck 17, and a screw 17a is formed around the neck. In this embodiment,
As shown in FIG. 1b, the coating films 12 and 13 are composed of a first layer (base layer) 12 having high work resistance provided from the upper end of the body portion 14 to the shoulder portion 16 and the neck portion 17, and the first layer 12. It is composed of a second layer (upper layer) 13 having a high corrosion resistance provided on the entire inner surface including. Instead of the monoblock can, it can be applied to a two-piece can or the like.

To manufacture such a metal container 10,
First, a blank material obtained by punching a thin metal plate into a circle is deep-drawn by a press to form a cylinder with a bottom, and in the case of a drawn and ironed can, the body is ironed to reduce the wall thickness. Then, the first layer paint is applied by powder coating or spraying to a predetermined area near the upper end opening of the inner surface of the obtained bottomed cylindrical can body. And in the wet-on-wet state,
That is, the coating material for the second layer 13 is applied by spraying without drying and curing (baking) the first layer. Then, the whole is dried and cured to form a coating film for the first layer 12 and the second layer 13. After forming the coating film on the inner surface, the shoulder portion 16 and the neck portion 17 are formed by mouth-drawing. Further, the curling 18 is formed by curling (when a flat portion is formed on the curling 18, crushing by a roll is performed at the same time), and the screw 17a is formed by screwing (stringing). The metal container 10 thus obtained is further washed and then filled with the contents.

The first layer 12 and the second layer 1 of the inner surface coating
The thickness of 3 is determined according to the material and thickness of the metal, the property of the contents, etc., but the thickness of the first layer 12 is usually 2 to 8 μm.
The thickness of the second layer 13 is usually about 2 to 10 μm, particularly about 4 to 7 μm. Various materials are used for each layer depending on the material of the metal and the nature of the contents, but since each layer is formed on the inner surface of the metal container, it has high adhesion and bondability to the metal surface and film formability. Those having high durability, elasticity and the like are preferable. As such a material, a curable synthetic resin is preferable, and a resin coating such as a thermosetting resin containing an epoxy group, a phenolic synthetic resin, or an epoxyphenol urea resin is particularly preferable. Among them, epoxy / phenolic resin coatings having high processing resistance and corrosion resistance are preferable. Further, since the first layer 12 and the second layer 13 are laminated on each other, it is preferable to use a combination of highly compatible ones such as synthetic resins of the same kind, those which are soluble in the same solvent, those which are cross-linked and hardened. .

For example, a combination in which the first layer is an epoxy / phenolic resin coating material having high workability and the second layer is an epoxy / phenolic resin coating material having high corrosion resistance is preferable as the first layer. As such a combination, for example, an epoxy / phenolic resin coating material containing no pigment or a small amount of pigment is used as the first layer, and an epoxy / phenolic resin coating material containing more pigment than the first layer is used as the second layer. As the second layer, an epoxy / phenolic resin paint having a pigment content higher than that of the first layer is used. Epoxy / phenolic resin coatings that do not contain pigments are relatively soft, and even when subjected to plastic processing with a high degree of processing,
This is because cracking and peeling are less likely to occur, and the inclusion of a pigment increases the hardness and improves the corrosion resistance, but decreases the workability.

Examples of the pigment contained in the second layer include inorganic pigments such as titanium oxide. However, an organic pigment may be used as long as it improves the corrosion resistance. Pigment content is 20-80wt%, especially 40-6
It is preferably about 0 wt%. Pigment content 20
If it is less than wt%, the corrosion resistance tends to decrease, and
This is because if it is 0 wt% or more, the work resistance becomes considerably poor. Although the average particle size of the pigment is not particularly limited, it is usually about 0.01 to 0.2 μm.

When the epoxy-phenolic resin has a large amount of phenol, the degree of curing is high. Therefore, the phenol content in the first layer is reduced to 10 to 30 wt%, particularly 15 to 20 wt%, and the second layer is reduced. By setting the phenol content to 20 to 50 wt%, particularly 22 to 30 wt%, the first layer paint and the second layer paint can be combined. In some metal containers, the epoxy / phenolic resin coating used for the second layer, which has low workability, may be used for the first layer in other metal containers having different metal types or low workability. is there. Even in that case, the ratio of the phenol content of the first layer is smaller than that of the second layer by about 1 to 20 points, preferably about 2 to 10 points.

Further, when the epoxy resin of the epoxy-phenolic resin has a high molecular weight, the hardness is high and the corrosion resistance increases, and when the molecular weight of the epoxy resin is low, the hardness is low and the workability is improved. Taking advantage of this point, the first layer is an epoxy / phenolic resin paint using a low molecular weight epoxy resin, and the second layer
The layer can also be an epoxy / phenolic resin coating using a high molecular weight epoxy resin. In that case, the average molecular weight of the epoxy resin in the first layer is 2,000.
0 to 10,000, preferably 2,000 to 7.0
The average molecular weight of the second layer is about 3,000.
About 20,000, preferably 5,000 to 20,000
It is about 0. The average molecular weight of the first layer is about 1,000 to 10,000 less than the average molecular weight of the second layer.

The molecular weight of the epoxy resin, the amount of the phenol component, and the presence / absence of a pigment may be employed in combination with each other. For example, a low molecular weight epoxy resin is used as the first layer, and an epoxy / phenolic resin coating with a reduced phenol content is used.
While using a high molecular weight epoxy resin as the second layer,
It is also possible to use an epoxy-phenolic resin having a large amount of phenol, or to make the second layer contain a pigment.

In the above-mentioned embodiment, the first layer and the second layer are resin paints mainly composed of epoxy / phenolic resin. For example, polyamide-imide resin paint, polyamide-based resin paint, epoxy-acrylic resin. Paint, vinyl chloride resin paint, vinyl organosol resin paint,
It is also possible to use conventional paints such as polyolefin resin paints. Even in those cases,
Differences in processing resistance / corrosion resistance were given depending on the presence / absence of pigment, high / low molecular weight, difference in ratio of contained components, etc. 2
Adjust the resin paints of different types, coat the parts with high workability with a high workability to form the first layer, and then paint the entire layer including the first layer with a high corrosion resistance to create the second layer. May be formed. In that case as well, if the resin paints are of the same type, the adhesion between the layers is high and peeling at the boundary is unlikely to occur.

Furthermore, a vinyl chloride resin is used for the first layer and a second layer is used.
It is also possible to adopt an epoxy / phenolic resin coating material having a lower workability and a higher corrosion resistance for the layer, or a combination of different kinds of materials for the first layer and the second layer.

An undercoat such as an epoxy resin may be interposed between the first layer or the second layer and the inner surface of the metal container, and an intermediate layer such as an epoxy resin may be provided between the first layer and the second layer. Other layer structures, such as intervening, can also be adopted. The container 10a of FIG. 1c comprises a third layer 1 of UV ink between the first and second layers and the inner surface of the metal container.
It has a three-layer structure in which 9 is interposed on all or part of the inner surface of the container. In this case, when the UV ink layer 19 is provided thickly, the number of pinholes is small and the corrosion of the metal surface due to the penetration of the contents can be remarkably prevented. This makes UV
It is possible to form a highly durable inner coating film without causing ink to exist on the coating film surface. This thickness is 3-100
It is preferably μm, particularly preferably 20 to 80 μm. Further, by using an epoxy resin coating material as the first layer and the second layer and using a radical polymerization type UV ink as the UV ink, the degree of welding or adhesion between both layers is high,
Peeling between both layers does not occur easily. Epoxy phenol resin is preferable as such an epoxy resin coating, and acrylic modified epoxy resin is preferable as the radical polymerization type UV ink. The UV ink layer 19 may be provided on the outermost layer above the first layer and the second layer. Even in the case of the outermost layer, by providing the UV ink layer 19, it is possible to reduce pinholes and prevent corrosion of the metal surface due to penetration of the contents. A hot melt agent may be used as the third layer. This makes U
By providing the same thickness as the V ink, it is possible to prevent corrosion of the metal surface due to penetration of the contents. This thickness is preferably 3 to 100 μm, particularly preferably 20 to 80 μm. Examples of such hot-melting agents include polyamide-based hot-melting agents, polyester-based hot-melting agents and the like. Among them, in consideration of coatability, a type having a low solvent viscosity (about 200 dpa · s / 200 ° C. or less) is preferable. . Furthermore, an epoxy / phenolic resin coating with high process resistance was used for the first layer, an epoxy / phenolic resin coating with high corrosion resistance was used for the second layer, and an epoxyphenolic resin coating with high process resistance was used for the third layer. A three-layer structure can also be used (see FIG. 7).

In FIG. 2a, a first layer 12 having a high work resistance is provided from the upper end of a body 14 of a can body 11 similar to that of the metal container 10 of FIG. 1 to a shoulder 16 and a neck 17, and corrosion resistance is provided in other parts. A metal container 20 provided with a tall second layer 13 is shown. As shown in FIG. 2B, the lower end of the first layer 12 has an inclined surface 21 in the range indicated by reference symbol R, which becomes thinner toward the lower end side, and the second layer 13 is superposed on the inclined surface 21 so as to have the same inclined surface. . Therefore, in the overlapping range R, the coating films have substantially the same thickness. It should be noted that the inclined surfaces may be simply overlapped without being formed. In that case, the thickness of the overlapping range R becomes thick. The manufacturing method of this metal container 20 is the same as that of the metal container 10 of FIG.
When coating the layer 13, the coating on the first layer 12 is simply omitted.

The first layer 12 and the second layer of this metal container 20
The layer 13 also has the same 2
Combinations of different materials can be employed. The thickness of each layer is also the same as in FIG. However, the first layer 1
The thickness of 2 can be somewhat thicker than in the case of FIG. 1, which can improve the corrosion resistance of the first layer 12. In this embodiment, the first layer 12 will be in direct contact with the contents. However, in such a metal container 20, contents are rarely filled up to the shoulder portion 16 and almost never filled up to the neck portion 17. Therefore, the first layer 12 on the inner surface of the shoulder portion 16 or the neck portion 17 is less likely to be eroded by the contents. Even if this is formed by necking the shoulder 16 and neck 17 after the inner surface is coated,
Further, even if the curling portion 18 or the screw portion 17a is formed, the coating resistance of the first layer 12 is high, and thus the coating film is unlikely to be cracked or peeled. Furthermore, since the second layer 13 is not provided on the first layer 12, the paint can be saved accordingly. 2c as in FIG. 1c.
The a has a third layer 19 made of UV ink between the first and second layers and the inner surface of the metal container and on the whole or a part of the inner surface of the container. This also reduces pinholes and prevents corrosion of the metal surface due to penetration of the contents.

3 to 6 show another embodiment of the metal container to which the above-mentioned separate coating with the first layer having high workability and the second layer having high corrosion resistance can be applied. The metal container 22 shown in FIG. 3 is an impact can having a so-called threaded portion with an inner coating film. The can body 11 is formed into a bottomed cylindrical shape by impact processing, and then a coating film is formed. Further, a thin portion 24 is formed between the neck portion 17 and the shoulder portion 16 by spinning or the like. The screw portion 17a is the cap 2
It is a male screw that is screwed with the screw portion 23a of No. 3, and airtightness is maintained by screwing. Therefore, the thread 17a has a considerably high degree of processing.

The metal container 26 of FIG. 4 represents a conventional aerosol can. In this product, slag such as aluminum or tin plate is formed into a bottomed cylindrical shape by impact processing, then an inner coating film is formed, and the shoulder portion 16 is necked.
The bead 18 is formed by curling.

The metal container 28 shown in FIG. 5 is a small aerosol container provided with an inner coating film. This product is made by impact molding a metal plate (slag) such as aluminum into a cylindrical shape with a bottom, and then applying inner surface coating, forming a shoulder portion 16 and a neck portion 17, and spinning the neck portion 17 by spinning. The groove 29 is formed. The annular groove 29 locks the valve 31 via a sealing material such as an O-ring 30,
This is for caulking the lower end edge of the cap 32. Reference numeral 33 is a gasket. Since this also fits the valve 31, the neck 17 and the annular groove 29 are highly processed.

The metal container 36 shown in FIG. 6 is a squeezed ironing can having a so-called screw portion for filling a soft drink or the like with the inner surface coated. This metal container 36 is opened to clearly show to the user that it is unopened, such as a pill fur proof cap (PP cap) or a similar alten cap (also known as flavor cap or high lock cap). A cap 37 having a skirt portion that breaks at times is used. Therefore, an annular groove 29 for crimping the lower end of the cap 37 is formed between the shoulder portion 16 and the neck portion 17 of the can body 11. Further, since such a cap 37 has a high strength, the neck portion 17 screwed to the cap 37 has a high strength and the molding precision is also high.

The metal containers 22, 26, 2 shown in FIGS.
In both cases 8 and 36, the same first layer as described above is formed on the inner surface in the region X where the degree of processing is high, and the above-mentioned second layer is formed in the region Y where the degree of processing is low (including regions where no post-processing is performed). Is formed. The second layer can also be provided on the first layer. These metal containers are also less likely to cause cracking or peeling of the coating film due to processing when the shoulder portion 16, neck portion 17, screw portion 17a, or annular groove 29 is formed, and have high corrosion resistance to the contents in other regions Y.

FIG. 7 shows a metal container 3 having a three-layer coating film.
8 shows eight embodiments. Similar to the metal container 10 of FIG. 1, this has a first layer 12 having a high work resistance in a region X having a high workability, and the entire inner surface including the entire first layer 12, that is, the workability is high. The second layer 13 having high corrosion resistance is provided on the entire region X and the region Y having low workability. Further in this embodiment, on the second layer 13,
In the same region X as the first layer 12, the third layer 39 having high workability
Is provided. This can further prevent the coating film from cracking or peeling in the region X where the workability is high. Moreover, the corrosion resistance to the contents is quite high. The same paint as in the case of FIG. 1 can be used for the first layer 12 and the second layer 13. Further, the coating material forming the third layer 39 may be the same as that of the first layer 12, or may be different as long as it has higher workability than the second layer.

The metal container 38a shown in FIG. 8 has a two-layer coating film formed on the entire inner surface of the container. That is, the coating film of the first layer 12 having high work resistance is formed on the entire inner surface of the container, and the second layer 13 having high corrosion resistance is formed on the entire first layer 12 so as to be superposed thereon. First layer 12 and second layer 13
The same paint as in the case of the metal container 10 shown in FIG. 1 is used as the paint. Also in this case, it is preferable that the second layer 13 is formed by wet-on-wet after the coating of the first layer 12 is provided, and then the second layer 13 is baked to cure. Since the first layer 12 is seamless and continuous, the durability of the first layer is high. Moreover, since the first layer 12 is entirely covered with the second layer 13 having high corrosion resistance, the corrosion resistance of the entire container is further increased. Although this can also use a coating having the same thickness as in the case of providing a substantially single-layer coating as shown in FIG. 2, the thickness of the coating of each layer is made thinner than those cases. You can also The thickness of the first layer 12 is, for example, 5 μm at the neck portion 17, 4 μm at the body portion 14, and 3 μm at the bottom portion 15.
The thickness of the second layer 13 is 3 μm at the neck 17,
It is about 4 μm at the body and about 5 μm at the bottom. Also, similar to metal container 10b of FIG. 1c, metal container 38b shown in FIG. 8b.
Provides a third layer 19 made of UV ink between the first layer and the inner surface of the metal container. Thereby, the metal container 10
Similar effects are obtained with b and UV ink. The thickness of the third layer 19 can also be adjusted according to the degree of processing of the container. For example, about 10 μm at the neck and the body 1
It is also possible to make it about 4 μm about 20 μm and the bottom part 15 about 20 μm.

FIG. 9 shows an embodiment in which the metal container of the present invention is applied to an extrusion tube. The extruded tube 40 is composed of a metal tube body 41 and coating films 44 and 46 provided on the inner surface thereof. The tube body 41 includes a cylindrical body portion 14, a frustoconical shoulder portion 16 continuous to the upper end thereof, and a cylindrical neck portion 17 extending upward from the upper end of the shoulder portion. A hem portion at the lower end of the body portion 14 is a bent portion 45 closed by a bending process. A screw member 48 made of synthetic resin is fitted and fixed to the outer periphery of the neck portion 17. A screw cap 49 is screwed onto the outer periphery of the screw member 48. In the tube body 41, the body portion 14, the shoulder portion 16 and the neck portion 17 are integrally formed by impact molding. Then, before the hem portion is bent, that is, in the state of FIG. 10a, coating and baking are performed on the inner surface of the container to provide the coating films 44 and 46.
Further, the inside of the container is washed and the open end (right end in FIG. 10a)
After the contents are filled in from, the hem is bent to form the bent portion 45 as shown in FIG. 10b.

In FIG. 10, FIGS. 10a and 10b
As shown in FIG. 5, the coating films 44 and 46 are formed on the inner surface of the bent portion 45 at the hem and have a high work resistance.
And the second layer 44 having high corrosion resistance provided on the inner surface of the first layer 46 and the inner surfaces of the body portion 14, shoulder portion 16 and neck portion 17.
Consists of. The thicknesses of the first layer 46 and the second layer 44 are almost the same, and are about 5 to 15 μm. The materials of the first layer 46 and the second layer 44 are the same as those of the metal container 10 shown in FIG. 1 and the same combination is used. The thickness of the body portion 14 is usually 0.1 to 0.1 in the case of aluminum.
It is about 0.2 mm.

This extruded tube 40 has the second layer 4 having high corrosion resistance on the inner surfaces of the body portion 14, the shoulder portion 16 and the neck portion 17.
Since 4 is provided, the metal surface is sufficiently protected from the contents. Moreover, since the post-processing (bending process) is not performed in the region Y, the relatively hard second layer 44 is not affected by the bending process and is not cracked or peeled. On the other hand, in the region X having a high degree of processing, that is, in the inner surface of the bent portion 45, the first layer 46 having high processing resistance and the second layer 4 formed thereon are provided.
Since No. 4 is provided, cracking and peeling hardly occur in the second layer 44 as well as in the first layer 46 even if bending with a high degree of processing is performed.

In this embodiment, the second layer 44 is provided on the entire first layer 46, but as in the case of FIG.
You may make it overlap only the edge part of the 2nd layer 44 on the 1st layer 46. In that case, the first layer 46 is exposed, but since the bent portion 45 is substantially not touched by the contents, there is little risk of corrosion. The metal container 50a shown in FIG. 11a includes a first layer 51 made of UV ink on the whole or a part of the inner surface of the can 11, and a first layer 51 made of a solvent-based paint having high corrosion resistance laminated on the first layer 51. The metal container 50b of FIG. 11b has a second layer 52 made of a solvent-based paint having a high work resistance on the entire inner surface of the can body 11.
And a first layer 51 made of UV ink laminated on the second layer 52. Since the first layer made of UV ink can be formed thick, pinholes are few and it is possible to prevent corrosion of the metal surface due to penetration of the contents. Also, after applying the first layer of UV ink,
Since it can be cured easily by irradiating with ultraviolet rays in a short time, the manufacturing facility is simple and it is suitable for mass production. The thickness is not limited, but is 3 to 100 μm,
It is particularly preferably 20 to 80 μm. Metal container 5
When the second layer made of a corrosion-resistant solvent paint is provided on the first layer as in No. 0a, the corrosion resistance of the bare coating film is further improved. Further, like the metal container 50b, by providing a solvent-based coating material having high workability as the second layer and providing the first layer thereon, the degree of welding between these coating film and the metal container is increased, Moreover, cracking and peeling can be further prevented.
The arrangement of the first layer and the second layer of the metal container 50a or the metal container 50b is not particularly limited, and the same effect can be obtained even if they are provided in reverse. However, it is most preferable to provide them in the order described above. A combination of a radical polymerization type UV ink and an epoxy resin paint is preferable as the first layer and the second layer. In this case, 2
High degree of adhesion between layers and high durability. Particularly, acrylic modified epoxy resin is preferable as the radical polymerization type UV ink, and epoxy phenol resin is preferable as the epoxy resin paint. Further, a coating film made of a hot-melting agent may be provided on the first layer of the metal container 50a shown in FIG. 11a. In this case as well, by providing a thick layer, it is possible to suppress the generation of pinholes and prevent corrosion of the metal surface due to penetration of the contents. Further, the hot melt agent can be effective in a short time, and is therefore preferable for mass production. The thickness is not limited, but is preferably 3 to 100 μm, particularly preferably 20 to 80 μm. Examples of such hot melt agents include polyamide hot melts and polyester hot melts.

Next, the effects of the metal container of the present invention will be described with reference to specific examples. [Example 1] As a material for the first layer having high work resistance, an epoxy / phenol ratio (hereinafter, referred to as E / P ratio) was 80.
A 20/20 epoxy / phenolic resin coating material was prepared, and an E / P ratio of 70/30 epoxy / phenolic resin coating material was prepared as the material of the second layer having high corrosion resistance. Outer diameter 53
The thickness of the first layer material is 3 to 5 μm on the entire inner surface of the semi-finished product of the bottomed cylindrical impact can with screw (mm thickness 0.45 mm, bottom thickness 1.1 mm). As described above, the material of the second layer was applied on the entire inner surface of the intermediate body including the first layer so as to have a thickness of 4 to 6 μm by wet-on-wet. Then, a baking process was performed to cure the first layer and the second layer. Further, the shoulder portion 16 and the neck portion 17 were formed by necking, and the bead portion 18 and the screw portion 17a were further formed to manufacture the metal container of Example 1.

Example 2 E / P was used as the second layer paint.
The ratio is 70/30 for epoxy / phenolic resin,
A metal container of Example 2 was manufactured in the same manner as in Example 1 except that a mixture of 53 wt% of the weight of the resin and a titanium oxide pigment was used. [Example 3] E / P / U (urea) as the second layer paint
Example 3 as in Example 1 except that an epoxy / phenol / urea resin paint having a ratio of 60/24/16 was used.
Of metal containers were manufactured. [Example 4] A metal container of Example 4 was produced in the same manner as in Example 1 except that an epoxy / phenolic resin having an E / P ratio of 78/22 was used as the second layer coating material.

[Comparative Example 1] A metal container of Comparative Example 1 was manufactured in the same manner as in Example 1 except that only the material for the first layer of Example 1 was applied to the entire inner surface of the semi-processed product as a coating film. . [Comparative Examples 2 to 5] Also, as a coating film, the second coating of Examples 1 to 4
Example 1 except that only the layers were coated on the entire inner surface of the semi-finished product
The metal containers of Comparative Examples 2 to 5 were manufactured in the same manner as in.

A full amount of 5% saline was poured into the metal container obtained as described above, and the energization value (average of N = 10) after 4 seconds at DC 6.3 V was measured between the inner surface and the outer surface. Measure
The degree of damage of the coating film during the post-processing was examined. Moreover, the corrosion resistance of the inner coating film of the body was examined under the following test conditions.
The results are shown in Table 1.

<Test conditions> • One perm solution (thioglycolic acid type or cysteine type) was filled. -Fill half the amount, set it horizontally, and leave it at 55 ° C for 2 weeks. -The degree of discoloration due to blistering at the gas-liquid interface and fine corrosion of the aluminum substrate and reaction product formation was visually observed.

[0060]

[Table 1] * (U) is the urea resin judgment standard ◎: No abnormality ○: There is an extremely slight abnormality, but there is no problem in practical use. Δ: There is a slight abnormality. X: Abnormal and practically problematic.

As described above, in Examples 1 to 4, the smaller the phenol content in the second layer, the better the current-carrying value (lower current value), and the greater the phenol content, the higher the corrosion resistance. However, in any of Examples 1 to 4, the first
It can be seen that the second layer has a good current-carrying value because of the presence of the layer, and no cracking or peeling has occurred. Also, regarding corrosion resistance,
High enough. Further, in Example 2 in which the second layer contains a pigment, the corrosion resistance is particularly improved. However, even in this case,
The energization value is good.

On the other hand, in Comparative Example 1 in which only the first layer is provided, it can be seen that although the energization value is good, the corrosion resistance is poor. In addition, in Comparative Examples 2 to 5 having only the second layer, the corrosion resistance is almost the same as that in Examples 1 to 3, but the energization value is extremely high at 60 mA or more except for those in which the epoxy-phenol-urea resin is laminated. It's getting worse. This is probably because the coating film was cracked or peeled during processing. In the case of Comparative Example 4 in which the epoxy / phenol / urea resin is laminated, as can be seen by comparing with Example 3, there is not much difference in the presence or absence of the first layer, but the corrosion resistance of the screw part with respect to the thioglycolic acid system Inferior to Example 3. Example 5 The metal container 50a shown in FIG. 11A of FIG. 11 was used as Example 5. A radical polymerization type acrylic modified epoxy resin is prepared as a material for the first layer composed of UV ink, and E / is used as a material for the second layer having high corrosion resistance.
An epoxy / phenolic resin paint having a P ratio of 70/30 was prepared. The thickness of the first layer material is 30 to 7 on the entire inner surface of the semi-finished product of the bottomed tubular impact can with an outer diameter of 53 mm (body thickness 0.45 mm, bottom thickness 1.1 mm).
It was coated so as to have a thickness of 0 μm, and ultraviolet rays having a wavelength of 370 nm were irradiated for 10 seconds to cure the first layer. After that, the second layer material is coated to a thickness of 8 to 12 μm,
The second layer was cured by baking at 230 ° C. for 7 minutes. Further, a neck portion was formed to form a shoulder portion and a neck portion, and a bead portion and a screw portion were further formed to manufacture. [Comparative Example 6] The same metal container as in Example 5 to which a single-layer coating film composed of only UV ink was applied was used as Comparative Example 6. A radical polymerization type acrylic modified epoxy resin is prepared as a material for the UV ink and has a thickness of 30 to 70 μm.
Then, the coating film was cured by irradiating ultraviolet rays having a wavelength of 370 nm for 10 seconds. Then, similarly to Example 5, a shoulder portion, a neck portion, a bead portion and a screw portion were formed to manufacture. Comparative Example 7 The same metal container as in Example 5 was coated with an epoxy / phenolic resin coating having an E / P ratio of 70/30 as a material having high corrosion resistance, and used as Comparative Example 7. Apply this to a thickness of 8-12 μm, and
It was baked at 0 ° C. for 7 minutes to be cured. Then, similarly to Example 5, a shoulder portion, a neck portion, a bead portion and a screw portion were formed to manufacture. Example 5, Comparative Example 6 obtained as described above
The energization value was measured by the method described above in Comparative Example 7. The results are shown in Table 2.

[Table 2] As described above, the energization values of the metal containers of Comparative Example 6 and Comparative Example 7 are relatively good, but the energization value of the metal containers used in Example 5 is significantly improved as compared with these Comparative Examples. . That is, it can be seen that the present invention remarkably suppressed the generation of pinholes in the inner coating film.

[Brief description of drawings]

FIG. 1a is a sectional view showing an embodiment of a metal container of the present invention, FIG. 1b is an enlarged sectional view of a main part thereof, and 1c is an enlarged sectional view of a waist portion where UV ink is provided on the inner surface of the container.

FIG. 2a is a cross-sectional view showing another embodiment of the metal container of the present invention, FIG. 2b is an enlarged cross-sectional view of a main part thereof, and 2c is a UV.
FIG. 3 is an enlarged cross-sectional view of a waist portion where ink is provided on the inner surface of a container.

FIG. 3 is a side view showing still another embodiment (impact can having a screw portion) of the metal container of the present invention.

FIG. 4 is a cross-sectional view showing still another embodiment (normal aerosol can) of the metal container of the present invention.

FIG. 5 is a cross-sectional view showing still another embodiment (small aerosol can) of the metal container of the present invention.

FIG. 6 is a side view showing still another embodiment (a squeezed ironing can having a screw portion) of the metal container of the present invention.

FIG. 7 is a sectional view showing still another embodiment of the metal container of the present invention.

8A and 8B are cross-sectional views showing still another embodiment of the metal container according to the present invention.

FIG. 9 is a cross-sectional view showing still another embodiment (metal tube) of the metal container of the present invention.

10A and 10B are cross-sectional views of a metal container according to still another embodiment of the present invention (metal tube) before and after post-processing.

11a and 11b are cross-sectional views showing yet another embodiment of the metal container of the present invention.

FIG. 12 is a cross-sectional view showing an example of a conventional metal container.

[Explanation of symbols]

10 10a Metal container 11 can body 12 First layer (coating film) 13 Second layer (coating) 14 torso 15 bottom 16 shoulder 17 neck 17a screw part 18 Curling (Bead) 19 UV ink layer 20 20a Metal container R overlapping range 21 slope 22 Metal container 23 Cap 23a screw part 26 metal containers 28 metal containers 29 annular groove 30 O-ring 31 valves 32 caps 33 gasket 36 Metal Container 37 cap X Highly processed area Y Area with low degree of processing 38a 38b Metal container 39 3rd layer 40 extruded tube 41 tube body 44 Second layer (coating film) 45 Bent section 46 First layer (coating film) 48 screw members 49 cap

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B65D 35/14 C09D 5/08 4J038 C09D 5/08 163/00 163/00 B65D 1/00 C F term ( (Reference) 3E033 AA02 AA04 BA07 CA11 CA12 DA02 DB01 DB03 EA20 FA01 GA02 3E062 AA04 AA20 AB01 AC03 JA01 JA02 JA07 JB23 JC02 JC07 JD03 3E065 AA01 BA01 BB10 DA04 EA21 DB13 BB17DA21 BB17DA42BB42 BB17 BB17 DA42 BB17BB23 EB13 EB15 EB22 EB32 EB33 EB35 EB39 EB52 EB56 4F100 AB01A AB10 AK33B AK33C AK33D AK36 AK53B AK53C AK53D AL05B AL05C AL05D BA03 BA04 BA07 BA10A BA10C BA10D CA13 CB03D CC00B CC00C CC00D DA01 EH462 EJ082 EJ542 GB16 HB00B HB00D JA20B JB02 JB02C JL01 JL01B YY00B YY00C 4J038 DB071 MA14 NA03 PB04 PC02

Claims (21)

[Claims] 1. A metal container, which has been subjected to plastic working with high workability in the vicinity of the opening on one end side after painting on the inner surface, wherein the coating film by painting is applied to at least the part with high workability. A first layer having a high work resistance provided and a second layer having a high corrosion resistance provided at least in a portion having a low workability are provided, and the entire inner surface of the container is covered with the first layer and the second layer. A metal container with a painted inner surface. 2. The metal container according to claim 1, wherein the metal container is a monoblock container that has been subjected to impact processing, drawing processing or drawing and ironing processing. 3. The metal container according to claim 1, wherein the plastic working with a high working degree is a screw working on the opening. 4. The metal container according to claim 1, wherein a third layer made of UV ink is provided on the whole or a part of the inner surface of the container. 5. The metal container according to claim 1, wherein a third layer made of a hot melt agent is provided on the whole or a part of the inner surface of the container. 6. The metal container according to claim 1, wherein the first layer is provided on the entire inner surface of the container, and the second layer is provided on a portion or the whole of the first layer having a low workability. 7. The metal container according to claim 1, wherein the first layer is provided in a portion having a high degree of processing, and the second layer is provided on the entire inner surface including the top of the first layer. 8. The metal container according to claim 7, wherein a coating film of a third layer made of the same material as that of the first layer is further provided on the second layer in a range corresponding to the first layer. 9. The first layer is provided in a portion having a high degree of processing, the second layer is provided in a portion having a low degree of processing, and is overlaid on the first layer in the vicinity of the boundary with the first layer. The metal container according to claim 1. 10. The metal container according to claim 1, wherein the first layer is an epoxy / phenolic resin coating material having high workability and the second layer is an epoxy / phenolic resin coating material having high corrosion resistance. 11. The metal container according to claim 8, wherein the first layer and the third layer are epoxy / phenolic resin paints having high process resistance, and the second layer is epoxy / phenolic resin paints having high corrosion resistance. . 12. The epoxy / phenolic resin coating material, wherein the second layer is a pigment-containing epoxy / phenolic resin coating material, and the first layer is pigment-free or has a smaller pigment content than the second layer. The metal container according to claim 1, wherein 13. The first layer has a phenol content of 10 to 3
0 wt% epoxy / phenolic resin paint, the second layer is 20-50 wt% epoxy / phenolic resin paint, and the first layer phenolic content is 1-20 points from the second layer The metal container according to claim 1, which is small. 14. The first layer is an epoxy / phenolic resin coating material using a low molecular weight epoxy resin, and the second layer
The metal container according to claim 1, wherein the layer is an epoxy / phenolic resin coating material using a high molecular weight epoxy resin. 15. The first layer is a water-based epoxy / acrylic resin coating material using a low molecular weight epoxy resin, and the second layer is a water-based epoxy / acrylic resin coating material using a high molecular weight epoxy resin. The metal container according to claim 1, wherein 16. A cylindrical container main body is formed from a material, and at least a part of the inner surface of the container main body near the opening provided at one end of the container main body is coated with a first layer having high work resistance, and then at least a part of the container is coated. Wet-on-wet coating of the second layer with high corrosion resistance is applied so that
The coating film is hardened, and then a plastic working having a high working degree is performed in the vicinity of the opening, and the first layer and the second layer cover the entire inner surface of the container. Container manufacturing method. 17. A cylindrical container body is formed from a material, UV ink is applied to the whole or a part of the inner surface of the container, and then the coating film is cured by irradiation of ultraviolet rays, and then at least the container body is covered. The inner surface in the vicinity of the opening provided at one end is coated with a first layer having high work resistance, and then a wet-on-wet type with high corrosion resistance is applied so that at least a part of it is overlaid on the first layer. Two layers of coating are applied, the coating film is cured, and then plastic processing with a high degree of processing is applied in the vicinity of the opening to cover the entire inner surface of the container with the first layer and the second layer. The manufacturing method of the metal container that has been painted. 18. A metal container, which has been subjected to plastic working with high workability in the vicinity of the opening on one end side after painting the inner surface, wherein the coating film by the painting is applied to the whole or one of the inner surface of the container. Coating on an inner surface having a first layer made of UV ink provided in a part and a second layer made of a solvent-based paint having high corrosion resistance or workability laminated on a part or all of the first layer. Metal container. 19. A metal container, which has been subjected to plastic working with a high degree of working in the vicinity of the opening on one end side after painting the inner surface, wherein the coating film by the painting is applied to the entire inner surface of the container or A coating is applied to the inner surface having a first layer made of a hot-melting agent provided in a part and a second layer made of a solvent-based paint having high corrosion resistance or high workability laminated on a part or all of the first layer. A given metal container. 20. The thickness of the coating film of the first layer is 3 to 10
The metal container according to claim 18, which has a thickness of 0 μm. 21. The metal container according to claim 18, wherein the first layer is made of a radical polymerization type UV ink, and the second layer is made of an epoxy resin paint.